import React, { useMemo } from 'react';
import {
  Bar,
  CartesianGrid,
  ComposedChart,
  Legend,
  Line,
  ReferenceLine,
  ResponsiveContainer,
  Tooltip,
  XAxis,
  YAxis,
} from 'recharts';
import type { ChickenWeight } from '../../types/api.ts';
import { formatDateId } from '../../utils/format.ts';
import { formatWeight, getTargetGainForAge } from '../../utils/weight.ts';

interface DailyWeightGainChartProps {
  rows: ChickenWeight[];
  docWeight: number;
}

type GainStatus = 'above' | 'near' | 'below' | 'none';

type ChartPoint = {
  day: number;
  date: string;
  gain: number | null;
  targetGain: number | null;
  status: GainStatus;
};

const DailyWeightGainChart: React.FC<DailyWeightGainChartProps> = ({ rows, docWeight }) => {
  const chartData = useMemo<ChartPoint[]>(
    () =>
      [...rows].reverse().map((row) => {
        const targetGain = getTargetGainForAge(row.age, docWeight);
        const gain = row.average_daily_gain;
        let status: GainStatus = 'none';
        if (gain != null && targetGain != null) {
          const threshold = Math.abs(targetGain) * 0.1;
          if (gain >= targetGain + threshold) status = 'above';
          else if (gain >= targetGain - threshold) status = 'near';
          else status = 'below';
        }
        return { day: row.age, date: row.date, gain, targetGain, status };
      }),
    [rows, docWeight]
  );

  const hasNoData = chartData.length === 0;

  const CustomLegend = () => (
    <div className="mt-2 flex flex-wrap items-center justify-center gap-6 text-sm text-gray-600">
      <div className="flex items-center gap-2">
        <div className="h-3 w-8 rounded-sm bg-red-600" />
        <span>Pertumbuhan Aktual</span>
      </div>
      <div className="flex items-center gap-2">
        <div className="h-3 w-8 rounded-sm bg-blue-600" />
        <span>Target Pertumbuhan</span>
      </div>
    </div>
  );

  const CustomTooltip = ({
    active,
    payload,
  }: {
    active?: boolean;
    payload?: Array<{ payload: ChartPoint }>;
  }) => {
    if (!active || !payload?.length) return null;
    const point = payload[0]?.payload;
    if (!point || point.gain == null) return null;
    const hasTarget = point.targetGain != null;
    const gainDiff = hasTarget ? point.gain - point.targetGain! : null;

    return (
      <div className="bg-white p-4 border border-gray-300 rounded shadow-lg">
        <p className="font-bold text-gray-800">Hari ke-{point.day}</p>
        <p className="text-sm text-gray-600">{formatDateId(point.date)}</p>
        <div className="mt-2 space-y-1 text-sm">
          <p>
            <span className="font-semibold text-red-600">Pertumbuhan Aktual:</span>{' '}
            {formatWeight(point.gain, { stripTrailingZeros: true })}
          </p>
          {hasTarget ? (
            <>
              <p>
                <span className="font-semibold text-blue-600">Target Pertumbuhan:</span>{' '}
                {formatWeight(point.targetGain!, { stripTrailingZeros: true })}
              </p>
              <p>
                <span className="font-semibold">Selisih:</span>{' '}
                <span className={gainDiff! >= 0 ? 'text-green-600' : 'text-orange-600'}>
                  {gainDiff! >= 0 ? '+' : ''}
                  {formatWeight(Math.abs(gainDiff!), { stripTrailingZeros: true })}
                </span>
              </p>
              <p>
                <span className="font-semibold">Status:</span>{' '}
                <span
                  className={
                    point.status === 'above'
                      ? 'text-green-600'
                      : point.status === 'near'
                        ? 'text-yellow-600'
                        : 'text-red-600'
                  }
                >
                  {point.status === 'above'
                    ? 'Di Atas Target'
                    : point.status === 'near'
                      ? 'Mendekati Target'
                      : 'Di Bawah Target'}
                </span>
              </p>
            </>
          ) : (
            <p>
              <span className="font-semibold text-gray-500">Target:</span>{' '}
              <span className="text-gray-400">Belum ada data standar</span>
            </p>
          )}
        </div>
      </div>
    );
  };

  return (
    <div className="bg-white p-6 rounded-xl shadow-sm">
      <div className="flex justify-between items-center mb-4">
        <h2 className="text-xl font-bold">Grafik Kenaikan Berat Harian</h2>
      </div>
      <div className="h-80">
        {hasNoData ? (
          <div className="flex items-center justify-center h-full">
            <div className="text-center">
              <p className="text-gray-500 text-lg font-medium">Tidak ada data tersedia</p>
              <p className="text-gray-400 text-sm mt-2">Data pertumbuhan belum tersedia</p>
            </div>
          </div>
        ) : (
          <ResponsiveContainer width="100%" height="100%">
            <ComposedChart data={chartData} margin={{ top: 5, right: 20, left: 10, bottom: 5 }}>
              <CartesianGrid strokeDasharray="3 3" stroke="#e0e0e0" />
              <XAxis
                dataKey="day"
                tick={{ fill: '#6b7280', fontSize: 12 }}
                label={{ value: 'Umur (hari)', position: 'insideBottom', offset: -5 }}
              />
              <YAxis
                tick={{ fill: '#6b7280', fontSize: 12 }}
                tickFormatter={(value) => formatWeight(value, { stripTrailingZeros: true })}
              />
              <Legend content={<CustomLegend />} />
              <Tooltip content={<CustomTooltip />} />
              <ReferenceLine y={0} stroke="#9ca3af" strokeWidth={1} />
              <Bar dataKey="gain" fill="#dc2626" radius={[8, 8, 0, 0]} name="Pertumbuhan Aktual" />
              <Bar
                dataKey="targetGain"
                fill="#2563eb"
                radius={[8, 8, 0, 0]}
                name="Target Pertumbuhan"
              />
              <Line
                type="monotone"
                dataKey="gain"
                stroke="#dc2626"
                strokeWidth={2}
                dot={false}
                activeDot={{ r: 5 }}
                connectNulls
              />
              <Line
                type="monotone"
                dataKey="targetGain"
                stroke="#2563eb"
                strokeWidth={2}
                dot={false}
                activeDot={{ r: 5 }}
                connectNulls
              />
            </ComposedChart>
          </ResponsiveContainer>
        )}
      </div>
    </div>
  );
};

export default DailyWeightGainChart;